I ended up removing the horizontal trim piece that runs along the door. i was then able to remove the upside-down U shaped channel that the window slides up and down in. This allowed me to insert the glass into the door cavity from outside the door. I carefully lowered it as far down into the door cavity as it would go and then reinstalled the U shaped channel and fed the window back up from inside the door. It’s now taped in place awaiting reconnection with the regulator.